People also somehow think that the post office won't be able to deliver so much mail. Which also doesn't make sense, it's a single envelope per house, they deliver more junk mail than that.
Edit: I should add I'm 100% in favor of mailin votes always, not just now. I simply do not believe that this postal slowdown is in any way connected to those who oppose it. And that's for the simple reason that it can't accomplish that.